WHAT IS THE manipulated variable and dependent variable. Hope and Elizabeth are trying to decide if they should buy a new skateboard or not. They want a skateboard that gives them the longest jump in the air off a ramp they've built. The new skateboard's designer claims to have an aerodynamic design that allows the longest air time possible when used correctly. Hope and Elizabeth's old skateboards don't have this aerodynamic design. They wonder if this if true and decide that Hope will buy the new skateboard to try out and Elizabeth will wait to see how it works before she buys one or not.